Try another dealership, even a Lincoln-Mercury dealer, if you are sick of dealing with that one dealership. Sounds like they won't ever get it right if they told you that the hesitation is gone and its not. A returnless Mystique has the same fuel pump as your 2000 SVT, and they have probably seen the same problem. Besides, L-M dealerships are generally more "customer oriented". They might hem and haw at the SVT, but explain to them that the problem you want them to look at is a system that is identical to the 2000 Mystique. Factory warranty should cover it all (Antonio had a 3rd party warranty).